Void filling joint prosthesis and associated instruments

Abstract

A distal femoral joint replacement system includes a femoral component having condylar articular surfaces, a stem extending from the femoral component, and a void filler for filling a bone void within a femur. The void filler includes a body and a plurality of legs extending from the body. The body has a sidewall defining an opening for receipt of the stem which extends along a length of the body and extends through the sidewall so as to form a side-slot in the sidewall that extends along an entire length of the sidewall. The plurality of legs each have a first end connected to the body and a second end remote from the body. The legs each have an outer surface that tapers between the first and second ends and is configured to register with a corresponding inner surface of a bone void when implanted in an end of the femur.

The invention claimed is: 
     
       1. A distal femoral joint replacement system, comprising:
 a femoral component having condylar articular surfaces; 
 a stem extending from the femoral component; and 
 a void filler for filling a bone void within a femur, the void filler having a body and a plurality of legs extending from the body, the body having a sidewall defining an opening for receipt of the stem extending along a length of the body and extending through the sidewall so as to form a side-slot in the sidewall that extends along an entire length of the sidewall, the plurality of legs each being frustoconically shaped and each having a first end connected to the body and a second end remote from the body, and wherein the plurality of legs each have an outer surface that tapers between the first and second ends and is configured to register with a corresponding inner surface of a bone void when implanted in an end of the femur. 
 
     
     
       2. The system of  claim 1 , wherein the sidewall of the body has a curved portion and a first and second wall portions intersecting the curved portion. 
     
     
       3. The system of  claim 2 , wherein the curved portion has a frustoconical outer surface and a cylindrical inner surface. 
     
     
       4. The system of  claim 2 , wherein the curved portion has an inner radius and the first and second wall portions each have a planar inner surface. 
     
     
       5. The system of  claim 4 , wherein the first and second wall portions intersect the curved portion such that the planar inner surfaces of the first and second wall portions are tangent to a cylinder defined by the curved portion. 
     
     
       6. The system of  claim 4 , wherein the first and second wall portions intersect the curved portion such that the planar inner surfaces of the first and second wall portions are tangent to a conical frustrum defined by the curved portion. 
     
     
       7. The system of  claim 1 , wherein the plurality of legs are separated from each other so as to form a gap therebetween for receipt of a portion of the femoral component, the gap is intersected by the opening and side-slot of the body. 
     
     
       8. The system of  claim 7 , wherein the gap is a box-shaped gap at least partially defined by inner surfaces of the legs and an end surface of the body, the box-shaped gap is configured to receive a cam-box of the femoral component. 
     
     
       9. A distal femoral joint replacement system, comprising:
 a femoral component having condylar articular surfaces; 
 a stem connected to and extending from the femoral component; and 
 a void filler for filling a distal femoral bone void and for supporting the femoral component when connected to an end of a distal femur, the void filler having:
 a body having an interrupted sidewall defining an opening for receipt of the stem extending entirely through the body and along a longitudinal axis thereof, the interrupted sidewall being interrupted by a side-slot communicating with the opening and extending along an entire length of the sidewall, 
 a lateral leg being frustoconically shaped, and 
 a medial leg being frustoconically shaped and extending from the body such that the side-slot is positioned between the lateral and medial legs in a lateral-medial direction. 
 
 
     
     
       10. The system of  claim 9 , wherein the lateral and medial legs define a gap that extends between inner surfaces thereof, the gap is sized to receive a portion of the femoral component therein. 
     
     
       11. The system of  claim 10 , wherein the gap intersects the side-slot and opening of the body. 
     
     
       12. The system of  claim 9 , wherein the lateral and medial legs each have a first end connected to the body, a second end remote from the body, and an outer surface that tapers outwardly from the first to the second end. 
     
     
       13. The system of  claim 12 , wherein an outer surface of the body is continuous with the outer surfaces of the lateral and medial legs. 
     
     
       14. The system of  claim 12 , wherein the outer surfaces of the lateral and medial legs comprise a porous material for promoting bony ingrowth. 
     
     
       15. The system of  claim 12 , wherein the outer surfaces of the lateral and medial legs comprise a porous and solid material, said solid material comprising peripheral edges of the lateral and medial legs so as to form rims of solid material that border regions of the porous material. 
     
     
       16. The system of  claim 12 , wherein an inner surface of the interrupted sidewall comprises a solid material and an outer surface of the interrupted sidewall comprises a porous material. 
     
     
       17. The system of  claim 12 , wherein the second end of each of the lateral and medial legs comprises a planar surface that faces a corresponding planar surface of the femoral component when the femoral component is connected to the void filler. 
     
     
       18. The system of  claim 9 , wherein each of the lateral and medial legs has a plurality of stepped surfaces positioned between the first and second end thereof.